Label‐Free Bioanalysis Based on Low‐Q Whispering Gallery Modes: Rapid Preparation of Microsensors by Means of Layer‐by‐Layer Technology

Low‐Q‐whispering gallery modes (low‐Q‐WGM) can be used for label‐free detection of interactions between biomolecules, measuring their binding and release kinetics or for analysis of changes in the medium in real‐time. The main advantage of the low‐Q‐WGM approach over other label‐free methods is the possibility of measurements in small cavities as the method uses microparticles down to 6 µm as sensors. Commercially available dye‐doped microparticles that are used as low‐Q‐WGM sensors exhibit several drawbacks. Therefore, alternative particle types are developed and optimized as low‐Q‐WGM sensors. First, dye‐doped particles made of different materials are screened. The most critical parameter for WGM performance is the refractive index (RI) of sensor particles. Furthermore, surface roughness of particles, determined by scanning electron microscopy and atomic force microscopy, affects their performance as WGM microsensors. In the second test, fluorescent dyes immobilized on nonfluorescent particles by means of nanometer thick layer‐by‐layer (LbL) films are shown to generate a strong WGM signal. The LbL‐coated particles show remarkably less background fluorescence than dye‐doped particles and are easier to prepare. Finally, this article proposes rapid preparation methods for WGM microparticle sensors based on various parameters such as material type, RI, surface roughness, and number of coated polymer layers.     

QoS‐aware LTE‐A downlink scheduling algorithm: A case study on edge users

4G/LTE‐A (Long‐Term Evolution—Advanced) is the state of the art wireless mobile broadband technology. It allows users to take advantage of high Internet speeds. It makes use of the OFDM technology to offer high speed and provides the system resources both in time and frequency domain. A scheduling algorithm running on the base station holds the allocation of these resources. In this paper, we investigate the performance of existing downlink scheduling algorithms in two ways. First, we look at the performance of the algorithms in terms of throughput and fairness metrics. Second, we suggest a new QoS‐aware fairness criterion, which accepts that the system is fair if it can provide the users with the network traffic speeds that they demand and evaluate the performance of the algorithms according to this metric. We also propose a new QoS‐aware downlink scheduling algorithm (QuAS) according to these two metrics, which increases the QoS‐fairness and overall throughput of the edge users without causing a significant degradation in overall system throughput when compared with other schedulers in the literature.     

The effects of exploration strategies and communication models on the performance of cooperative exploration

Exploration with mobile robots is utilized in a wide range of applications including search and rescue missions, planetary exploration, homeland security, surveillance, and reconnaissance. Cooperative exploration offers the potential of exploring an unknown zone more quickly and robustly than single-robot case. However, coordinating multiple robots is a challenging task due to heterogeneous processing and communication requirements, and the complexities of exploration algorithms. This paper presents a comparison of different cooperative exploration strategies, such as frontier-based exploration, market-driven exploration, and role-based exploration, based on their exploration performances and processing time requirements. To show the effect of CPU power on the processing time of the exploration algorithms, two notebooks and a netbook with different specifications have been extensively used. Comparative simulation results of our own application developed in Java show that the processing time requirements are consistent with the computational complexities of the exploration strategies. The results we obtained are consistent with the CPU power tests of independent organizations, and show that higher processing power reduces processing time accordingly.     

Suitability of acid whey for fermented and fresh-pack cornichon pickle production

Suitability of acid whey (AW) as brine media in fermented and fresh-pack cornichon pickle production was investigated. Fermented and fresh-pack pickles were produced with AW and vinegar (control). Microbiological, textural, colour and sensory properties of the pickles were monitored during 12-wk storage at room temperature. Fermented and fresh-pack pickles manufactured with AW exhibited higher total solids content than the pickles manufactured with vinegar. Acid whey as pickling media increased the development of presumptive lactococci species both in fermented and in fresh-pack pickles. This study shows that AW is a suitable pickling media for fermented and fresh-pack cornichon pickle manufacture.     

Adaptive multi-view video streaming using side information over peer-to-peer networks

Multimedia Tools and Applications - Multi-view plus-depth-map (MVD) video streaming with autostereoscopic displays provides multi-user immersive media experiences. In this context, delivery of MVD...     

Adsorption of phthalic acid and its esters onto high-area activated carbon-cloth studied by in situ UV-spectroscopy

The adsorption behavior of phthalic acid and its three esters dimethyl phthalate, diethyl phthalate and diallyl phthalate onto high-area activated carbon-cloth was studied by in situ UV-spectroscopic technique. The effect of ionization of phthalic acid on its adsorption was examined by carrying out the adsorption process in three media; water, 1 M H(2)SO(4) and 0.005 M NaOH. Maximum adsorption was observed in 1 M H(2)SO(4) and almost no adsorption in 0.005 M NaOH. These results were discussed in terms of electrostatic and dispersion interactions between the adsorbate species and the carbon-cloth surface taking the point of zero charge (pH(pzc)) of the carbon-cloth into account. The adsorption process for the phthalate species studied was found to follow the first-order rate law, and the rate constants were determined. The isotherm data for the adsorption of phthalic acid and its esters were derived experimentally and fitted to Langmuir and Freundlich isotherm equations. Both equations were found to represent the experimental isotherm data almost equally well.     

Antifungal,Mechanical, and Physical Properties of Edible Film Containing Williopsis saturnus var. saturnus Antagonistic Yeast

The molding of food products causing health risks is a main problem in the food industry. In this study, as an alternative solution for preventing mold growth, an antifungal edible film was developed by incorporating Williopsis saturnus var. saturnus (0; 3; 7; and 9 logs CFU/cm²) into whey protein concentrate (WPC) based films. Antifungal properties of the films against Penicilium expansum and Aspergillus niger were analyzed using the disc diffusion method. Physical (barrier, solubility, color), mechanical (tensile strength and percent elongation) properties of the films as well as the survival of W. saturnus in the film were assessed during 28 days of storage at 23 °C. According to the results, the viability of W. saturnus (7 and 9 logs CFU/cm²) in WPC films stored for 28 days under vacuum or non‐vacuum decreased to 36% and 60%, respectively. In addition, films containing W. saturnus decreased the viability of P. expansum and A. niger by 29% and 19%, respectively. Adding yeast did not change the tensile strength (P > 0.05), but significantly decreased % elongation and increased water vapor and oxygen permeability and water solubility (P < 0.05). In conclusion, this study showed that the developed films may be useful for inhibiting mold growth on foods.     

Determination of chloride and nitrate in butter,margarine, cheese and meat products using ion selective electrodes

Chloride analysis was quite easy and salt contents of all butter and margarine samples were found to be less than 2 g NaCl/kg while those of cheese and meat products were above 10 g/kg. Nitrate analysis was not as easy as chloride analysis due to interferences of chloride and organic ions. These interferences were tried to be eliminated using either Al₂(SO₄)₃ and Ag₂SO₄ solutions or aluminium and silver resins. Results showed that the elimination of interferences is most effective with the use of resins in amounts of 3 g under the present experimental conditions. Nitrate contents of meat products analysed were found to be less than 20 ppm.     

Cellulose-based edible films and their effects on fresh beans and strawberries

 Cellulose-based edible films were applied to fresh beans and strawberries. The moisture loss from these food was measured following the application of films of varying composition under different conditions. The effects of the method of application of film solution, the amounts of polyethylene glycol (PEG), stearic acid (SA), palmitic acid (PA) and lauric acid (LA) in the film, the molecular weights of methyl cellulose (MC) and PEG and, finally, the relative humidity of the environment on moisture loss from fresh beans and strawberries coated with films were investigated. The brushing method for the application of film solution to the foods was found to be better than wrapping and dipping methods in terms of reducing the moisture loss. Recommended amounts of PEG-400 and fatty acids in film solution to reduce moisture loss from foods were found to be 11 ml and 40 g per 100 g MC-20000, respectively. A slight decrease in moisture loss was observed when PEG-400 and MC-20000 in the film solution were replaced by PEG-1000 and MC-41000, respectively. Finally, it was found that moisture loss from fresh beans and strawberries coated with films decreased as the relative humidity of the environment in which they were kept was increased. Received: 19 December 1996 / Revised version: 20 May 1997